Geology topics

Jennifer M.K. O’Keefe

Publications and source records attributed to Jennifer M.K. O’Keefe.

3 recordsLinked to original sources

USGS2011

Quantifying greenhouse gas emissions from coal fires using airborne and ground-based methods

Coal fires occur in all coal-bearing regions of the world and number, conservatively, in the thousands. These fires emit a variety of compounds including greenhouse gases. However, the magnitude of the contribution of combustion gases from coal fires to the environment is highly uncertain, because adequate data and methods for assessing emissions are lacking. This study demonstrates the ability to estimate CO 2 and CH 4 emissions for the Welch Ranch coal fire, Powder River Basin, Wyoming, USA, using two independent methods: (a) heat flux calculated from aerial thermal infrared imaging (3.7–4.4 t d −1 of CO 2 equivalent emissions) and (b) direct, ground-based measurements (7.3–9.5 t d −1 of CO 2 equivalent emissions). Both approaches offer the potential for conducting inventories of coal fires to assess their gas emissions and to evaluate and prioritize fires for mitigation.

International Journal of Coal Geology↗

USGS2010

CO 2 , CO, and Hg emissions from the Truman Shepherd and Ruth Mullins coal fires, eastern Kentucky, USA

Carbon dioxide (CO 2 ), carbon monoxide (CO), and mercury (Hg) emissions were quantified for two eastern Kentucky coal-seam fires, the Truman Shepherd fire in Floyd County and the Ruth Mullins fire in Perry County. This study is one of the first to estimate gas emissions from coal fires using field measurements at gas vents. The Truman Shepherd fire emissions are nearly 1400 t CO 2 /yr and 16 kg Hg/yr resulting from a coal combustion rate of 450–550 t/yr. The sum of CO 2 emissions from seven vents at the Ruth Mullins fire is 726 ± 72 t/yr, suggesting that the fire is consuming about 250–280 t coal/yr. Total Ruth Mullins fire CO and Hg emissions are estimated at 21 ± 1.8 t/yr and > 840 ± 170 g/yr, respectively. The CO 2 emissions are environmentally significant, but low compared to coal-fired power plants; for example, 3.9 × 10 6 t CO 2 /yr for a 514-MW boiler in Kentucky. Using simple calculations, CO 2 and Hg emissions from coal-fires in the U.S. are estimated at 1.4 × 10 7 – 2.9 × 10 8 t/yr and 0.58–11.5 t/yr, respectively. This initial work indicates that coal fires may be an important source of CO 2 , CO, Hg and other atmospheric constituents.

Kentucky↗

USGS2009

The Tiptop coal-mine fire, Kentucky: Preliminary investigation of the measurement of mercury and other hazardous gases from coal-fire gas vents

The Tiptop underground coal-mine fire in the Skyline coalbed of the Middle Pennsylvanian Breathitt Formation was investigated in rural northern Breathitt County, Kentucky, in May 2008 and January 2009, for the purpose of determining the concentrations of carbon dioxide (CO2), carbon monoxide (CO), and mercury (Hg) in the vent and for measuring gas-vent temperatures. At the time of our visits, concentrations of CO2 peaked at 2.0% and > 6.0% (v/v) and CO at 600 ppm and > 700 ppm during field analysis in May 2008 and January 2009, respectively. For comparison, these concentrations exceed the U.S. Occupational Safety & Health Administration (OSHA) eight-hour safe exposure limits (0.5% CO2 and 50 ppm CO), although the site is not currently mined. Mercury, as Hg0, in excess of 500 and 2100 μg/m3, in May and January, respectively, in the field, also exceeded the OSHA eight-hour exposure limit (50 μg/m3). Carbonyl sulfide, dimethyl sulfide, carbon disulfide, and a suite of organic compounds were determined at two vents for the first sampling event. All gases are diluted by air as they exit and migrate away from a gas vent, but temperature inversions and other meteorological conditions could lead to unhealthy concentrations in the nearby towns. Variation in gas temperatures, nearly 300 °C during the January visit to the fire versus < 50 °C in May, demonstrates the large temporal variability in fire intensity at the Tiptop mine. These preliminary results suggest that emissions from coal fires may be important, but additional data are required that address the reasons for significant variations in the composition, flow, and temperature of vent gases.

Kentucky↗